Your fighter (the one with the red headband and black belt) fights on its own.
Defeat opponents to earn EXP. Each level-up offers 3 picks: new skills, skill upgrades or stat boosts.
Equipped skills go into your fighter's combo rotation, each on its own cooldown. You have 5 slots; swapped-out skills wait in your bag and come back when you pick their upgrade.
Check Next ▸ at the top: each opponent type has a weakness. Pick skills that counter it.
Beat a boss to earn a special for the gold ★ slot. It charges as you deal and take damage. You fire it: tap ★ or press Space.
Score = opponents defeated (stronger = more) + time survived.